Polymers for acrylic fibers having improved dyeability



3,366,711 POLYMERS FOR ACRYLIC FIBERS HAVING IMPROVED DYEABILITY Corrado Mazzolini, Mestre, Venezia, and Luigi Patron, Venice, Italy, assignors to Monsanto Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed May 3, 1966, Ser. No. 547,196 7 Claims. ((1 260-898) ABSTRACT OF THE DISCLOSURE Basic dyeable acrylic polymers have been prepared through interpolymerization of acrylonitrile, other monoethylenically unsaturated monomers having bulky side groups and additionally small concentrations of sulfocinnamic acid, its alkyl, halogen, hydroxyl and water soluble salt derivatives. Such polymers and blends thereof with other acrylic polymers have been found useful in the preparation of basic dyeable acrylic fibers.

This invention relates to novel interpolymers of acrylo-,

nitrile and articles of manufacture prepared therefrom having improved basic dyeability. The invention further relates to polymer blends comprising the novel interpolymer in admixture with other polymers.

Interpolymers of acrylonitrile with monoethylenically unsaturated monomers copolymerizable therewith and blends of these polymers with one or more different acrylic polymers are known to be suitable for the manufacture of fibers having excellent properties for textile applications. One basic limitation on the usefulness of such polymers and polymer blends is their resistance to basic dyes.

Acrylonitrile polymers which have been prepared through the use of redox initiated polymerization techniques contain sulfonic acid and sulfate acid end groups on the polymer chain resulting from catalyst fragments. These groups assist dyeability to a small degree. However, the concentration of acid groups attached to the polymer resulting from catalyst fragments is found to be inversely proportional to the molecular weight of the polymer. Thus, the concentration of residual acidic groups in polymers having molecular weight in the fiber-forming range is too low to render the polymer attractive to adequate concentrations of basic dyestufis which provide deep color shades necessary for a broad range of textile applications.

The basic dyeability of acrylonitrile polymers can be improved by interpolymerizing acrylonitrile with compounds having a free acid function such as acrylic acid, methacrylic acid, itaconic acid and the like. However, improvements of basic dyeability in the manner just described are usually obtained only by sacrificing color and heat stability of the polymers and fibers produced from them.

Another technique for enhancing the basic dyeability of fibers obtained from acrylic polymers can be accomplished by interpolymerization of alkenyl sulfonic acids or vinyl aromatic sulfonic acids (usually in the form of their water soluble salts). While the presence of such sulfonic acid groups increases the polymer afiinity for basic dyestuffs, the utility of many known monomers for this purpose is diminished because they are difiicult to incorporate along the polymer chains and because they tend to reduce conversion during polymerization.

It is an object of this invention to provide novel interpolymers of acrylonitrile having improved afiinities for basic dyestuffs without sacrifice of polymer color and heat stability.

Another object of the invention is to provide novel interpolymers of acrylonitrile having improved aflinities methyl acrylate,

for basic dyestuffs whereby monomer incorporation into the polymer is efiicient.

Then too, an object of the invention is to enhance the basic dye aflinity of known polymers and fibers prepared therefrom by the provision of blends of known acrylic polymers with the novel interpolymers of this invention.

These and other objects of the invention are accomplished by interpolymerization of acrylonitrile with other monoethylenically unsaturated monomers copolymerizable therewith in the presence of a monomer having the formula CH=CHC OH and water soluble alkali metal, alkaline earth metal and ammonium salts thereof wherein n is an integrer from 1 to 2, m is 0, l or 2 and R is a substituent selected from the group consisting of lower alkyl, halogen and hydroxyl.

Although vinyl monomers bearing negative groups on both aliphatically unsaturated carbon atoms normally interpolymerize with acrylonitrile only sparingly, the recited sulfocinnamic acid and derivatives thereof are surprisingly readily incorporated into the polymer chain and greatly increase the polymer affinity for basic dyes.

Moreover, interpolymerization of compounds such as sulfocinnamic acid does not adversely affect the heat stability of the polymers. Another unexpected property possessed by the interpolymers of this invention is that the concentrations of basic dyestuffs absorbed by fibers made from the polymers appear to be independent of pH variations below pH 7.

The interpolymers of this invention are prepared by interpolymerizing a mixture of monomers containing at least by weight of acrylonitrile, up to 14.95% by weight of one or more different monoethylenically unsaturated monomers interpolymerizable therewith and from 0.05% to 2% by weight of a sulfocinnamic acid compound. or water soluble salt thereof represented by the above recited formula.

The monolefinically unsaturated monomers copolymerizable therewith are exemplified by compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, methoxymethyl methacrylate, oz-ChlOfOfiCI'YliC acid, vinyl chloride, vinylidene chloride, l-chloro-l-bromo ethylene, methacrylonitrile, acrylamide, methacrylamide, a-chloroacrylamide, methyl vinyl ketone, vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl stearate, N- vinylimides, styrene, vinyl naphthalene, Z-methyl-S-vinylpyridine and other vinyl monomers known to those skilled in the art.

Examples of the sulfocinnamic acid compounds illustrated by the above recited formula are compounds such as:

B-(2-methyl-4-sulfophenyl)acrylic acid ,8-(2-ethyl-4-sulfophenyl)acrylic acid ,8-(2-isopropyl-4-sulfophenyl) acrylic acid fl-(2,3-dimethyl-4-sulfophenyl)acrylic acid ,H-(2,3-diethyl-4-sulfophenyl)acrylic acid fi-(2-chloro-4-sulfophenyl) acrylic acid ,6-(2,3-dichloro-4-sulfophenyl) acrylic acid fl-(2-hydroxy-4-sulfophenyl)acrylic acid ,6- 3,4-disulfophenyl) acrylic acid Water soluble salts of these compounds such as the sodium and ammonium salts are desirably employed for purposes of polymerization.

Of the polymers falling within the scope of this invention those having p-sulfocinnamic acid interpolymerized are preferred because of availability of the monomer and high incorporation in the polymer molecule.

The polymers of this invention can be prepared using bulk, solution, suspension or aqueous emulsion techniques generally known in the art for vinyl polymerization. A preferred method involves the formation of an containing the sulfocinnamic acid monomer. Total water was fed at a rate of 2.3 liter/hr. and the total monomer fed was 0.5 liter/hr. The aqueous polymerizate was discharged through an overflow pipe and filtered to remove aqueous suspension of monomers and initiators at a pH 5 the polymer after which the polymers were washed with of below 7. Free radical forming initiators such as perwater, washed with acetone and then given another waoxides, persulphates, perborates and the like can be emter wash prior to drying in an oven at 80 C. for 12 hrs. ployed. The preferred initiator is a redox system compris- The following determinations were carried out on the ing a sulphoxy reducing agent such as sulphurous anhypolymers thus obtained:

dride, sodium sulphite, magnesium suphite and bisulphite l0 Conversion expressed as percent by weight of obtained and equivalent sulphurous compounds wherein the sulpolymer with respect to the weight of the introduced furous ion has a valence of 4 or less in combination with monomers.

a catalyst having radicals such as persulfate, percarbonate, Intrinsic viscosity [7;], calculated from relative visperoxy, and perborate. Polymerization is carried out by cosity determination, expressed in d1 grnf from which continuous, semi-continuous and batch polymerization 15 was calculated the viscosity average molecular weight techniques until polymers in the fiber-forming molecular (TL) 01 the polymers using the formula of Cleland and weight range are formed at which time the polymerizast k 2 33 1 4 M0.75 Relative viscosity tion is ShOITStOPPed- The POIYIIIer Contents of the p y is the viscosity of a solution of 0.1 gm. of the polymer in erization vessel are separated by filtration, then washed 100 1 f dimethylformarnide (DMF) divided by the n dried. viscosity of DMF, both measured at C.

The dried polymer can be dissolved in conventional B i dyeability expressed as the percent of polymer Organic Solvehts for acrylic P l Such as dimethyl" Weight of commercial (purity about 18 percent) Sev10n acetamide, dimethylformamide, dimethylsulfoxide and l 2 1 Basie Blue 22 dye fi d by the pglymey ethylene Carbonate if desired, aqueous Salt Solution from a solution containing about 7 grams per liter of said such as sodium thiocyanate, zinc chloride, lithium bro- 25 d t a li to polymer ratio f 40 to 1, a H bf 53 mide and the like y he used- The P y (101365 of and a temperature of 100 C. over a 2 hour period. SOllltlOi'lS may thfil'l be CXtI'lldBd t0 fOl'l'I'l filaments by Wfit Color of the pglymers was measu gd .by means of the y p g t c niques. integrating General Electric Recording Spectrophotom- The basic dyeability of polyacrylonitrile or interpolyeten mers containing at least about 85 weight percent of acry- Th l t bili was d i d b h i h 1 lonitrile and one or more monoethylenically unsaturated mers f 8 hours at 145 c h variation i eo1or b IIIOhQIheTS copolymerizahle therewith y he enhanced tween the unheated polymers and heated polymers was by blending therewith the above described dye receptive measured by means of the integrating General Electric polymers of this invention. Where polymer blends are Recording S t h t used in the manufacture of fibers, it is desirable to form h results f h determinations Carried out f each Separate polylht3r Solutions in a common SOlVQnt d then polymer containing the various acid comonomers used admix the solution prior to spinning. Desirably, the for increasing the basic dyeability are recorded in the folweight of the acidic monomer unit based on the polymer lowing table:

TABLE 1 Percent; by Basic Dye- Original Color Thermal Sta- Weight of ability in of the Copolybility of the Ex. No. Acid Comouomer Used to Increase the Added Corn- Conversion, Intrinsic Percent of mer, Percent Copolymer Dyeabihty onomer Based Percent Viscosity Sevron Blue on Total 2G Fixed Monomer P B A P A B 2 Acrylic aci 0.5 68.8 1.60 14.2 98.2 94.5 15.1 16.0 3 Itaconic acid 0. 68. 2 1. 16 98.1 94. 6 14. 9 16. 2 4 p-Methacrylanudobenzene sulfonic acid. 0.5 67. 2 1.44 14. 9 98. 5 93. 4 13. 5 14. 6 5 pVinylhenzene sulionic acid 0.5 68. 5 1. 73 1.5.1 98. 5 94. 4 13. 2 15. 8 6.. p-Sulfociuuamio acid 0.3 71. 7 1. 51 14. 0 98. 5 03. 0 12. 4 14.1 7 do 0.5 70.0 1. 02 16.2 98.9 94.2 12.6 14.5 s do. 1 68.2 1.74 17.2 98.9 93.0 12.2 14.5 9 ClO 1.5 64.1 1.93 20.4 98.7 92.4 13.7 15,8 10 do 2 63.2 1. 97 22.0 98.8 92.7 14.0 15.6

blend is maintained at levels between 0.05 percent and In the measurement of color the P (purity) gives the 2,0 percent, 60 measure of how near the color shade is to the neutral The improved affinity for basic dyes is illustrated in color (white-grey-black axis of the color solid). The the following examples by dyeing the modified polymers brightness B shows how near the color of the sample as of this invention at 100 C. for two hours with a dye reflectance of the incident light is to the white. solution containing about 7 grams per liter of dye. The The polymers obtained according to Examples l-10 quantity of dye fixed on the polymer is then measured were spun under identical conditions, from a solution of spectrophotometrically. dimethylformamide by means or normal wet-spinning procedures into a spin bath composed of water and di- Examples 1 -1 0 methylformamide. The fibers thus obtained were oriented A 3 liter polymerization vessel was continuously fed by stretching, washed in water, dried and collapsed. The separate aqueous streams of catalyst (14 8 0 and activafibers were then subjected to the following determinations: tor (S02) containing and Weight Perest based Color of the fiber: Measured by means of the integrating on total monomer, respectively. The pH of the S0 stream General Electric Recording Spectrophotometer was adjusted to about 3 y adding M11003. A stream Basic dyeability: Carried out by dyeing at 98 c.-100 Containing 91 Weight Percent aclylohih'ile and 9 Weight s C. for 3 hours, with a ratio bath/ fiber of 50:1, by using percent of vinyl acetate Was fed with a separate stream the dye Red Astrazon BBL (Cl. Basic Red 14) and Variation of the dyeability of the fiber with the varying nitrile and vinyl acetate were oopolymerized in -a ratio of 94 parts of acrylonitrile to 6 parts of vinyl acetate.

This polymer,- 88 parts, was mixed with 12 parts of a copolymer composed of 50% of acrylonitrile and 50% of pH of th dye bath i percent .b i ht f d b- 5 of 2-methyl-5-vinylpyridine and was'then wet-spun under sorbed by the fiber. i the same conditions as in Example 12.

The results of the determinations,carried out for each The fibers thus obtained have the properties .recorded fiber, are reported in Table H. in Table IV.

TABLE III Original Thermal v Percent by Intrinsic Conversion, Dyeability, Polymer Color Stability Added Acid Comonomer Weight of Viscosity Percent Percent Acid Added [a] 5 P B A P A B 5 1.50 70.1 11.7 93.5 93.9 12.7 14.9 Itaconic'acid 0.4 1.52 68.6 14.2 98.3 04.7 14.8 15.2 Acrylic acid 0.5 1. 57 68.5 14.1 98.2 94.6 14.7 14.0 Vin; Lb'enzenc sulphonic ac 0.5 1. 54 68. 4 14. 6 98.1 94. 5 13. 8 15.1 p-Suliocinnamic acid 1. 51 70. 2 16. 2 98.8 94. 6 12.3 14.2

TABLE II TABLE IV Color of Dyeability Percent of Dye Fiber Obtained the Fiber Percent Dye Absorbed by the Fibers Obtained According to the Color of Flber gfifsg gf 8y Ulsing thef i lgndtlie tFiber Fiber at pH Example (Red As-tmzon 0 61' 0 e S razon irn iq o. BBL P I B BBL) P117 P B 3.2 4.3 I 5.4

12 01.0 77.4 1,4 05.3 79.5 3.0 as 3.8 3.0 13 94.8 78.5 4.2 3.6 4.1 4.2 94.7 "-78.2 5.0 4.2 4.6 5.0 04.3 78.7 4.3 3.7 3.1 4.3 84.0 78. 9 3.2 2.2 2.: gg

5. 7v ,70. 95.0- 710.3 5.; We dalm- 95.0 79.1 s. I 9L9 79.0 ml M 10 0 10.1 1. A novel interpolymer compnsing, 04.8 70.0 12.1 11.8 12.0 12.1 (a) at least about 85 percent by weight of acrylonitrile, Y (b) from about 0.05 to about 2.0 percent by weight of a mo 0 Example 11 40 H n mer selected from the group consisting of compounds represented by the formula Mixtures of monomers composed of 91% of acrylonitrile and of 9% of methyl acrylate, and an additional quantity of various .acid comonomers introduced to increase the dyeability,,were polymerized according to Ex- (soamn 0 ample 1. l

Under the standard polymerization conditions about OHTCH 6011 300 g./hr. of copolymer were obtained in which acrylonitrile and methyl acrylate are copolymerized in a ratio of 93 parts of acrylonitrile to 7 parts of methyl acrylate.

Results of determinations were made on the polymers as in Example 1 and are recorded in Table III. ffl all g r r m 1 to 2, m 18 0 to 2 and R s a substituent group selected from the group con- Example 12 f l slsting o ower alkyl, halogen and hydroxyl and A mixture of monomer composed of 92% of acrylomwater soluble salts of said compounds and,

trile and 8% of vinyl acetate were polymerized according to Example 1.

Under the standard polymerization conditions above 300 g./hr. of polymer of acrylonitrile and vinyl acetate were copolymerized in a proportion of 94 parts of acrylonitrile to 6 parts of vinyl acetate.

A mixture of 88 parts of said polymer with 12 parts of a polymer of nearly of 50% of acrylonitrile and 50% of 2-methyl-2-vinylpyridine was dissolved in dimethylacetamide and spun acording to the wet-spinning described in Example 1. The fibers thus obtained gave the properties recorded in Table IV.

Example 13 To a mixture of monomers constituted of 92% of acrylonitrile and 8% of vinyl acetate was added 1% of p-sulfocinnamic acid based on the weight of the a-crylonitrile/ vinyl acetate mixture and this ternary mixture was polymerized according to Example 1.

Under the standard polymerization conditions above 300 g./hr. of polymer were obtained in which acrylo- (c) up to about 14.95 percent by weight of at least one other different monoethylenically unsaturated monomer interpolymerizable therewith.

2. The novel interpolymer of claim 1 wherein n is l and m is 0.

3. A fiber comprising the interpolymer of claim 1.

4. A novel polymer blend which comprises (a) the interpolymer of claim 1 and (b) at least one other polymer comprising in the absence of monomer (b) of claim 1 at least about percent by weight of acrylonitrile and up to 15 percent by weight of at least one other monoethylenically unsaturated monomer copolymerizable therewith.

5. A fiber comprising the polymer blend of claim 4.

6. In a process for interpolymerization of acrylonitrile,

the improvement which comprises contacting a mixture of said acrylonitrile in the presence of an initiator for vinyl polymerization with a monomer selected from the 7 group consisting of compounds represented by the formula (SOaHL. O

-CH=CHI(I)OH wherein n is an integer from 1 to 2, m is 0 to 2, and R is a substituent selected from the group consisting of lower alkyl, halogen and hydroxyl and water soluble salts thereof and at least one other different monoethylenically 11nsaturated monomer interpolymerizable therewith.

7. The improvement of claim 6 wherein n is 1 and m is 0.

References Cited UNITED STATES PATENTS 2,913,438 11/1959 Davis et al.

5 3,067,161 12/196'2 Roth. I

3,202,641 8/1965 Nakajirna et al. 3,256,252 6/1966 Kruckenberg et al.

10 MURRAY TILLMAN, Primary Examiner.

I. WHITE, Assistant Examiner. 

